Reciprocating mounting means for mounting thereon a sanding or like tool



Oct. 25, 1960 B. A. SWANSON 2,95

RECIPROCATING MOUNTING MEANS FOR MOUNTING THEREON A szmnmc; OR LIKE TOOLFiled March 29, 1956 3 Sheets-Sheet 1 JNVENTOR. flex-17am If 5wans on177 TORNEY Oct. 25, 1960 B. A. SWANSON ,9

RECIPROCATING MOUNTING MEANS FOR MOUNTING THEREON A SANDING OR LIKE TOOLFiled March 29, 1956 3 Sheets-Sheet 2 -J h 158 i Q 5 3 n5- (5 5/ 57 5/57a r 5s IN VEN TOR.

Bernard 1?. Swanson ATTORNEY Oct. 25, 1960 B. A. SWANSON 2,957,232

RECIPROCATING MOUNTING MEANS FOR MOUNTING THEREON A SANDING 0R LIKE TOOLIN V EN TOR.

Bernard l2 Jn'msoh ATTORNEY United States Patent O'ice RECIPROCATINGMOUNTING IVIEANS FOR MOUNTING THEREON A SANDING OR LIKE TOOL Bernard A.Swanson, Sacramento, Calif. (Bellevue, Wash.)

Filed Mar. 29, 1956, Ser. No. 574,913

7 Claims. (Cl. 51-170 My invention relates to a reciprocating mountingmeans for mounting thereon a sanding or like tool.

More particularly, my invention relates to a reciprocating mountingmeans characterized by the facility and controlability with which it maybe employed due to its freedom from transmitting objectionable vibratingimpulses to the hand of the operator when there is mounted thereon asanding, polishing, scraping, rubbing, massaging, or like device. 7

Present devices commonly employed for the purposes indicated present aserious objection as to the small power directly available to performwork.

There is also a great objection to present devices, for accomplishingthese various purposes, occasioned by the severity and magnitude of thevibratory impulses transmitted to the hand of the operator as commonlyin use.

Another objection to present devices of the types indicated is theirweight and bulkiness which, combined with the generation of vibrationsin the hand of the operator, cause rapid operator fatigue.

Another objection is the relatively large compressed air supplyrequirements of such prior devices. In short, said devices customarilyand inefliciently employ and require a large volume of fluid pressure tooperate the .same. Such devices, complicated in their structure, arevery costly in manufacture, and likewise are very costly to operate.

A primary object of my invention is to overcome all of the aboveobjections and difliculties.

Particularly it is a primary and fundamental object of my invention toprovide the mechanism set forth characterized by having a motor of thefluid pressure reciprocatory type which develops effective high speedreciprocatory movement, with far greater reciprocation speeds than likedevices commonly employed for accomplishing like purposes.

Further, it is a primary object of my invention to provide such a devicewhich economically develops exceedingly great working power inproportion to the volume of fluid pressure employed.

A further primary and fundamental object of my invention is to provide amechanism characterized by a structure and mode of operation which doesnot permit the stalling of the motor regardless of the degree ofpressure with which the device is held against the work. Such pressuremay be of such magnitude that even stalling of the vibratory plate orbase will not stall or injure the motor and will not injure or fatiguethe operator, nor will such operator lose control of the mechanismregardless of the size of the unit. Normally, compressed air constitutesa dangerous source of power should the device become stalled, i.e. itwhips the device about so that the operator normally loses control andeven may become seriously injured.

A further primary object of my invention is to provide a device of theclass described which does not depend for its effectiveness upon thevibratory force reacting upon the hand of the operator.

Patented Oct. 25, 19.60

Also, it is a primary object of my invention to cushion by fluidpressure the reciprocating piston so that the piston does not developits vibratory force by direct contact with the end walls of the motorcylinder.

Also, it is a primary object of my invention to provide a mechanismcharacterized by having the motor mounted upon a vibratory tool mountingplate or base vibrationally independent of the handle housing by whichthe device is manipulated by the operator.

. An object of the invention is to provide a machine which willefiectively sand or polish various objects and surfaces, which machinemay be portable if desired.

Another object of the invention is to provide a sanding and polishingmachine which embodies a reciprocating sanding or polishing block whichis actuated by an air engine of the reciprocating type, whereby the toolcan be readily used for sanding woodwork, scraping and polishingsurfaces, and sanding out rust spots, or for rubbing and massagingpurposes, as desired.

A further object is to provide a pneumatic sanding and polishing machinewhich is extremely simple and inexpensive to manufacture and to operate,and which may be designed to be portable if desired.

Further and more specific objects of the present invention involvepresentation of various forms thereof, including one form of theinvention wherein the mechanism comprises a motor and base plateassembly, the motor including a cylinder fixedly secured to said baseplate, with handle means in spaced relation to said base plate andflexible means exhibiting three-dimensional resiliency connecting saidhandle means and said assembly at the base plate of the latter, andpresentation of another form of the invention wherein such flexiblemeans connects said handle means and the cylinder of said assembly.

Other objects and advantages will be apparent to those skilled in theart from the following description of various typical embodiments of theinvention, set forth by way of illustration and not limitation.

For purposes of clarity and readiness of understanding, and not by wayof limitation as to field of application, my invention is set forthbelow as applied to sanding, scraping, rubbing, polishing, and massagingdevices.

The foregoing general objects of my invention, together with othersinherent in the same, are attained by the mechanism illustrated in thefollowing drawings, throughout which like reference numerals indicatelike parts: 7

Figure l is a view in longitudinal medial cross-section, with variousparts in side elevation, of a tool embodying my invention, showing thereciprocatory piston 'at one stage of travel;

Fig. 2 is a view partly in side elevation and partly in longitudinalmedial cross-section of the same, showing the reciprocatory piston atanother stage of travel;

Fig. 3 is a view in cross-section substantially on broken line 3-3 ofFigure 1;

Fig. 4 is a detached view in side elevation of a motor and base plateassembly according to the present invention;

Fig. 5 is a view in transverse vertical cross-section similar to Figure1, but showing a modified form of tool according to the presentinvention which is provided with scraper blades, and is well adapted foruse as a paint scraper;

Fig. 6 is a fragmentary view partly in plan and partly in horizontalcross-section showing an elastic and resilient connecting means, ofmodified form as used in the machine shown in Fig. 5, for providingvibrational separation between a handle housing and a reciprocatory toolcarrying assembly supporting and guided by said handle housing;

Fig. 8 is a fragmentary. cross-sectional partial view of the other endpart of the block or base plate and scraper blade assembly shown in Fig.7, showing the scraper blades inclined in an opposite direction;

Fig. 9 is a detached fragmentary perspective partial viewfshowing ascraper blade and scraper blade frame means; a a

Fig. 10 is a detached fragmentary perspective partial view, showingscraper blade frame means and devices for holding scraper blades whilethey are being sharpened;

Fig. '11 is a view in cross-section of a modified form of the scraperblade showing the bottom portion hollow Fig. 12 is a view of a modifiedform of the blade cutting mechanisnyeach of which comprises a group orplurality of blades contacting each other substantially throughout theirwidth;

Fig. 13 is a fragmentary perspective partial view of a modified form ofthe center or intermediate blade of the form of the blade cuttingmechanism shown inFig. 12;

Fig. 14' is a view in longitudinal medial cross-section,

'with various parts shown in side elevation, of a modified form ofmechanism embodying by invention, wherein the resilient connecting meansbetween the motor and base plate assembly and handle housing comprises arectangu-v lar flexible casing connecting to said motor and base plateassembly at the lateral edges of the cylinder thereof;.and Fig. 15 is aview in transverse vertical cross-section of the modified form of theinvention illustrated in Fig. 14, taken substantially along line 1515thereof.

Referring in detail to the drawings, Figs. 1 to 4, in-

clusive, the said machine of my invention comprises a housing 10 whichis adapted to be conveniently gripped. in the users hand, and thehousing 10 is provided with a fluid pressure passageway 11. A fitting 12is arranged on the housing 10 in registry with the passageway 11,

whereby a suitable hose 13 can be connected thereto for carrying fluid,such as compressed air, from a source of supply, not shown. Aspring-pressed control valve 14' is arranged in the passageway 11 fornormally preventing flowof fluid therethrough, and a manually-operableactu ating member 15 is connected to the valve by a stem 16, theactuating member 15 being pivoted to the housing and forth. The saidbase plate 21 is provided with a channelway 22 which is connected to thepassageway 11in the housing 10 by means of a flexible hose 23. Therbaseplate 21 is dependingly'supported below the housing 10 by means of aflexible or rubber strip 24. The upper end of the strip 24 is secured tothe housing 10 by metal strap 25, there'being screws 26 projectingthrough the strap 25, the rubber strip 24, and into the housing 10. Aplurality of L-shaped brackets 27 are secured to the base plate 21 bysecuring elements, such as bolts 28, and the lower por-' tions of therubber or flexible strap 24 is secured to the brackets .27 by means of aretaining band 29 anda plu rality of screws 30.

Positioned between the plate 19 and the base 21 is an engine or motor 31of the fluid pressure operated reciprocatory type. The engine comprisesa cylinder 32 which maybe connected to the base or plate 21 by athreaded brushing or nipple 33 whereby movement of the cylinder2,957,:asa

32 causes movement of said base plate 21. Headed bolts 34 further securethe base 21 to the cylinder 32. Reciprocatingly arranged in the cylinder32 is a piston 35 which receives compressed air from the port or annularrecess 36 in the cylinder 32. The piston 35 is provided with a pair ofspaced passageways 37 and 38 which alternately discharge air againstopposite ends of thecylinder 32 and thereby cause independent movementof both the cylinder 32 and piston 35 so that the cylinder 32 is alsofree to reciprocate. The piston 35 has a hill-lug 35a and 35b at eachend and a third hill-lug 35c intermediate said ends. Said third hill-lug350 has lateral valleys 35d and 35e on each side thereof and also afluid pressure inlet starting groove 35 which groove has'a seepagestarting conduit 35g connecting said groove 35f with one of saidconnecting conduits or' passageways such as 38. The air exhausts throughthe aperture or exhaust ports 39 in the cylinder 32, then through theopenings 20 in the plate 19, and finally out through the bore 40 in thehousing. v

V A strip of abrasive 41, such as sandpaper, is carried by a snap-onlocking or mounting plate 43, anda rubber pad 42 is interposed betweenthe abrasive sheet or strip 41 and the snap-on plate 43 whichhasresilient rolled ends 44 adapted to snap into notches 45 of base plate21.

In use, compressed air or other fluid is conveyed through the housing 10in ,controlled amounts, andthe fluid causes the piston 35 to reciprocatein cylinder 32 and thereby likewise cause Said cylinder 32 toreciprocate and thereby cause the base 21 carrying the abrasive sheet 41to move back and forth.

The fluid, pressure operated mo'tor herein set forth and itsadvantageous characteristics are more fully described and claimed in 'myco-pending application Ser. No. 390,617, filed November 6, 1953, now US.Patent No. 2,821,962, entitled Engines, which application is in turn acontinuation-in-part of my application Ser. No. 97,661, filed June 7,1949, and entitled Fluid Pressure Operated Reciprocatory Vibratory SheetMetal Cutting Shears, and to which reference should be made for a morecomprehensive consideration of the details and advantageous featuresthereof.

The piston 35 is cushioned in its're ciprocatory movement by theinrushing air. The sudden stoppinglof the piston 35 imparts its momentumto the cylinder 32. The piston 35 and cylinder 32 both reciprocate asjust set'forth so that the operator will experience a minimum of recoil,while maximum power will be delivered by the machine. The machine thussands and polishes by reciprocating movement of the abrasive sheet 41,in contrast to the conventional circulatory movement of abrasive sheets.

The scraper shown in Figs. 5 to 10 includes parts as follows, which aresimilarv to'the correspondingly numbered parts in Figs. 1 to 4: Ahousing 10, inlet and control means for fluid under pressure 11 to 17,inclusive, and 23, and motor parts 31, 32, and'35 to 39, inclusive. Inthe interest ofbrevity, the description of these parts is not hereinrepeated.

A reciprocable block or base plate 21a, shown in Figs. 5,7, and 8, issimilar to the base plate 21 shown in Figs. 1 to 4, and is provided witha passageway 22a similar to the passageway 22, and is secured to themotor 31 by screws 58 which correspond to the screws 34' of Figs. 1 and2.

The flexible and elastic mounting means shown in Figs; 5 and 6 forconnecting the handle housing 10 with the reciprocable block or baseplate 21a is in the formof a box-shaped connector member of rubber,polyethylene, or like elastic material exhibitingthree-dimensionalresiliency. The resilient mounting means as shown inFigs. 5 and 6 is' the preferred form of a rectangular flexible housing,i.e., box-shaped housing. Such resilent mounting means comprises a planeflat bottom 50, two end walls 51 and two transversely corrugated sidewalls 52. An inwardly extending flange 53, integral with both the endwalls 51 and side walls 52, extends around the top of the flexiblemounting means. The flange 53 seats within an external groove 54 whichextends around the bottom portion of the housing 10. A metal clamp band55 ex tends around the upper marginal portion of the end walls 51 andside walls 52 and secures the flexible mounting means to the housing 10.Preferably the clamp band 55 has two out-turned, perforated end portions55a which are connected by a bolt 56 so that the band 55 may betightened like a hose clamp on the flanged part 53 of the flexiblemounting means or connector. One of the outturned end portions 55a andthe bolt 56 are shown at the right in Fig. 5.

The elastic end walls 51 are of fairly thick rubber, for example, andwill transmit a substantial amount of downward pressure from the housingagainst the motor and base plate assembly and the scraperparts carriedthereby, while at the same time said end walls 51 will bend or flexfreely, notwithstanding said downward pressure, to permit reciprocationof the scraper parts relative to the handle housing 10. The corrugatedside walls 52 are thinner than the end walls 51 and the corrugationsextend between the bottom 50 and the top flanges 53 of the walls 52, andthese corrugated walls 52 will flex and bend more easily in directionslongitudinally of the tool than a non-corrugated piece of like elasticmaterial of the same dimensions, as will be apparent.

The bottom 50 of the flexible mounting means or elastic connectingmember rests on the reciprocable base plate 21a. A metal plate 57, whichpreferably has upwardly curved edges 57a, is positioned within therectangular or box-shaped flexible housing or elastic connector memberand rests on the bottom 50 thereof. The motor 31 rests on the plate 57and said motor and the plate 57 and bottom member 50 and reciprocablebase plate 21a are all rigidly connected together by the screws 58. Asuitable fitting 59, similar to fitting 33 of Figs. 1 and 2,communicatively connects the flexible conduit member 23 with thepassageway 22a in the base plate 21a.

The ends of the base plate 21a are provided with grooves 60, shown inFig. 8, to releasably receive the curved upper edge portions 61 ofresilient end walls 62 of a blade carrying frame of rectangular shape.The blade carrying frame is thus quickly and easily attachable anddetachable with respect to the base plate 21a by snapping the curvedportions 61 thereof into and out of the notches 60 in the ends of saidbase plate 21a. Each side of the blade carrying frame is shaped somewhatlike a letter J in cross section (see Figs. 9 and 10) and comprises anouter flange 63, a bottom part 64, and an inner notched flange 65 whichis provided with notches 66. The resilient end walls 62 are fixedlysecured to the sides 63, 64, and 65 of the blade carrying frame at thecorners.

Preferably the two opposed edges or sides of each notch 66 are closesttogether in a plane coincident with the top surface of the bottom part64, and'these opposed notch sides diverge from each other verticallyconsidered from this plane so that scraper blades 67 will be supportedfor pivotal movement in this plane of the top surface of the bottom 64,as hereinafter described.

Each scraperblade 67 is a plane flat piece of steel or like metal with anotch 68 of inverted L-shape adjacent each end thereof, said notches 68leaving blade supporting end parts 69 of narrower width than the bladeson the ends of the blades. The blades supporting parts 69 are adapted torest on the bottom 64 of the blade carrying frame and the adjacentportions of the blades are positioned in the notches 66.

The notches 66 hold the blades firmly and at the same time thedivergence of these notches allows said blades to rock or pivot betweenthe inclined positions as shown respectively in Figs. 7 and 8. Thisapplies the blade corners along the bottom or outer edges of the bladesto the work at an angle best calculated for efiicient scraping.

A rectangular blade retaining frame 70 is positioned,

6 within the blade carrying frame in close proximity to the upper edgesof the blades 67. The ends of this frame 70 are releasably but firmlyreceived within depressions 71 in the resilient end parts 62 of theblade carrying frame. The thrust of the blades 67 is exerted against theframe 70 when the scraper is applied to an object to be scraped and theframe 70 prevents the blades 67 from falling out of the blade carryingframe when said blade carrying frame is detached from the reciprocablebase plate 21a. The blade retaining frame 70 can be snapped into thenotches 71 and is readily removable therefrom.

In the form of this invention shown in Fig. 5, fluid under pressurefirst exhausts through the ports 39 into the housing 10 and thencepasses through perforations 72 in parts 57, 50 and 21a and discharges orblows out between the blades 67. The exhaust fluid is thus used todislodge scrapings from between the blades 67 and keep the scraper cleanwhile it is in use, thereby greatly increasing the efiiciency of thetool. The bottom or outer portions may be hollow ground, if desired,thereby increasing the cutting or scraping action of the corners oredges.

In the operation of the scraper shown in Figs. 5 to 10, inclusive, themotor 31 provides rapid reciprocation of the base plate 21a and scraperparts carried thereby as hereinbefore explained in connection with Figs.1 to 4.

Fig. 11 shows a blade 77 of modified form having a hollow ground workengaging edge 78 which may be advantageously used in some types of work.

Fig. 12 lllustrates a form of the invention in which each blade unit orblade cutting mechanism is made up of a group or plurality of separateblades 79 in juxtaposed or side-by-side contacting relation. In thisform of the invention in which each blade unit is made up of a pluralityof separate blades, each blade unit presents or applies a plurality ofscraping edges to the work. The blade bottom or outer portions may beflat or hollow ground as desired;

Fig. 13 shows a blade 80 with a notched or serrated or saw-toothed workengaging edge 81 and which is preferably used between two of the blades79 shown in Fig. 12. This form of intermediate blade functions to cutfast and break up a heavy coating of paint, or to quickly smooth down arough surface for finishing.

If the corners of the scraping edges of the blades of the form shown inFig. 5 become dull or rounded, they may be quickly and easily restoredto a sharp condition by first applying to the scraper suitable means, asshown in Fig. 10, which Will prevent pivotal movement of the blades andwill rigidly hold the blades perpendicular to the base plate 21a, andthen placing the blades on a plane but rough abrasive surface andreciprocating the blades by supplying energy to the motor 31. One flatabrasive surface which could be used for sharpening would be sand oremery cloth or a paper supported on a flat plate. One device which maybe used to rigidly secure the blades 67 in planes perpendicular to theplane of the reciprocable base plate 21a is shown in Fig. 10. Thisdevice comprises a bar or plate 73 having notches 74 adapted to fit overthe blades 67 and hold these blades rigid and parallel and perpendicularto the base plate 21a. Devices are provided for rigidly securing thenotched bar 73 to the bottom part 64 of one side of the blade carryingframe. These devices may be cap screws 75 extending through holes orslots 76 in the bar 73 and threaded into the frame part 64. Either oneor two of the bars 73 may be used on a scraper, as

desired, and these bars may either be detached when not in use or, insome instances, may be retracted clear of the blades 67 and leftattached to the scraper.

Turning to a consideration of a further modified form of the presentinvention as illustrated in longitudinal and transverse cross-sectionalviews in Figs. 14 and 15, respectively, such further form of theinvention typifies and alternative manner of vibrationally isolating themotor and base plate assembly of the mechanism fi'om More specifically,the modified form of theinvention illustrated in Figs. 14 and l is shownwith the mechanism at rest, i.e., with its plate assemblyin a centralposition with respect to the vibration cycle. As illustrated, themechanism comprises a housing 100 provided with a. fluid pressurepassageway 101. A fitting B12 is threaded- ;ly retained in housing 106in registry 'with said passageway 101', and a fluid pressure deliveryline such as a hose, 'a segment of whichis shown at 103, delivers fluidunder pressure to said passageway 101 from a suitable source of."supply, not shown. A ball control valve 104, spring pressed by spring104a, is arranged in passageway 101 for regulating flow of fluidtherethrough, and'a manually operable actuating member 105 ismechanically engaged with ball valve 194 by a stem 106, said actuatingmember 165 being pivoted to. housing 100 by pin 107.

Fibrous mass 1&3, such as asbestos, brass Wool or other non-corrodingair-entraining material having sounddeadening properties is contained inthe interior of housing 109 and maintained in position therein by meansof a;removable plate 199, which is in turn provided with a plurality ofspaced passageways 110 permitting passage the'rethrough of exhaustingfluid medium from motor 31. a A tool mounting base plate 111 is providedwith a channelway 112 connected to passageway 101 in housing 100 bymeans of a flexible hose .113.

I Engine 31 comprises a cylinder 32 fixedly connected to base plate 111by means. of a threaded bushing or nipple 33 and bolts 34.Reciprocablyarranged in cylinder 32 is a piston 35 receivingfluid'medium under pressure from annular recess 36 in cylinder 32.Piston 35 is provided with a pair of spaced passageways '37 and 33 whichalternately discharge exhausting fluid medium again'st opposite ends ofthebore of cylinder 32 in a manner so that both piston 35 and cylinder32reciprocate, the fluid medium under pressure exhausting throughexhaust ports 39 in cylinder 32, thence through openings 110 in plate109, and finally out to the atmosphere through the bore 130 in housing100. It will be apparent thatcylinder'32, piston 35, and otherassociated elements the rnotor assembly are identical with correspondingelements of the forms of the invention illustrated in Figs. 1 and 5, forexample, and have been assigned like identification numerals.

It will be further apparent that base plate 111 is substantiallyidentical with base plate 21 and base plate 21a "in the inventionillustrated in Fig. 5, and that said tool mounting plate 111 can readilyserve to mount various tools or work performing elements similar tothose disclosed in connection with said base plates 21 and 21a, asdesired.

As in the forms of the invention earlier discussed, the

form thereof illustrated in Figs. 14 and includes a tool mounting baseplate and a reciprocatory motor includlng a cylinder .fixedly mountedwith respect to said base plate, such base plate and motor forming whatmay be termed a motor and base plate assembly. In the form of theinvention illustrated in Figs. 14 and 15, this motor and baseplate'assembly is connected at the lateral edge of cylinder 32 thereofto the handle means comprising housing 100 by means of a flexible casing.120,

which is advantageously of relatively thin rubber construction and whichis afiixed to said lateral edges of dimension and is advantageouslyrelatively thin in charac'ter. Said casing 120 functions generally inthe same manner as casing 24 in the form of the invention illustrated inFig. l, and casing 50 in the form of the invention illustrated in Fig.5to vibrationally isolate housing from the reciprocating motor and baseplate assembly when the latter generates high frequency reciprocatoryvibrations. Although shown in Figs. 14 and 15 as being moulded or formedwith flat Walls of substantially even thickness, itwill be apparent thatcasing 'can be of corrugated or other similar configuration along one ormore axes offvibration, such as along the principal or longitudinal axisthereof like side walls 52 of casing 50 in Fig.6, as desired; a V g Itis to be noted further that the upstanding wall portions provided by allof these forms of resilient connecting means serve to permit asubstantial degree of vibrations of the motor assembly longitudinally,laterally, rotatively, and even vertically with respect'to theassociated handle housing 10 or 100, and thus effectively isolates thehandle housing and the hand of the operator from such vibrations, evenwhen substantial downward pressure is applied against the handle meansto increase the working action of. the tool.

It will be evident that the vibrational isolation of the hand of theoperator from the vibrations of the motor and base plate assemblycharacteristic of the present invention is achieved by connecting'aflexible means of the type here presented from the handle means eitherdirectly to the base plate or to the cylinder of the motor of theassembly. However, in practice it has been found preferable to connectsuch flexible means from the handle means directly to the base plate, asin the forms of the invention shown in Figs. 1 and 5, since sucharrangement thereby provides a relatively longer ventical dimension ofthe flexible casing with a relatively lower and more compact overallvertical dimension of the mechanism. Further this form of the inventionas a result of its relative compactness exhibits better guiding controland a comparatively greater degree of vibration isolation because thevibrations of the motor are in part absorbed by the tool action beforebeing transmitted to the flexible casing.

Mode of operation Much of the mode of operation of the mechanisms of myinvention herein is set forth above in connection With the descriptionof the construction. of said devices.

With fluid operated reciprocatory sanders of common practiceconstruction, so far as known to applicant, the eflectiveness of thedevice as respects sanding of the workobjectdepends, apart from theguiding function of the hand, solely upon the reaction against the handof the operator to cause the device to have the necessary pressure foroperation against the Work. 'That is, the force directed against thework requires in such device reaction of equal magnitude against thehand of the operator. Such construction involves the vibratory plate orbase being rigidly connected to the vibratory reciprocating piston andthe handle of the device being relatively fixed in at least onedimension of vibration with respect to the reciprocating mechanism.Therefore, a considerable degree of vibration is necessarily transmittedto the operator, and when the hand of the operator ceases to press thedevice against the work and the hand is removed from the device, suchdevice will no longer operate as a sander but will go out'of control andjump about in non-sanding actiongover the work.

In contrast, *applicants device operates as V a sander, scraper, or likedevice, to the extent of the weight of the machine with thefluidpressure turned on and the hand of the operator removedguiding ofthe device over the work may even be done by pulling the device over thework with a cord or string. The device will not go out "of control inthe sense that occursin the case ofsaid "c m p v i e structure referredto above. If greater sanding effect is desired, then greater weight maybe added and the device may be manipulated by leading it by a cord.Thus, the hand of the operator, with my device, may be used to increasethe pressure contact of the device upon the work as a weight. Thus, itwill be apparent that the mode of operation of the device of theapplicant is clearly different from that of the conventional structuredefined.

The unanchored and freely reciprocating piston 35 is free to impart itsimpulses to the cylinder 32. It is unanchored and free to reciprocatebecause it is not directly connected to the vibratory or reciprocatorybase plate 21. If it were so connected, i.e., integrally formed, then bypressing the device hard against the work (i.e., the piece being sandedor scraped or polished, etc.) the piston could be stalled if saidmounting plate for the abrasive sheet (in case of the sander) is heldstill and immovable. But in the device of my invention, there is no suchintegral interconnection and the piston is free to respond to the fluidpressure.

Since many embodiments can evolve incorporating this inventive concept,and since many modifications can be made in the embodiments hereinbeforeshown and described, it is to be understood that all matter herein is tobe interpreted merely as illustrative and not in a limiting sense, andthat such further modifications are to be construed as being within thescope of the present invention, as defined by the following claims.

This application is a continuation-in-part of my copending applicationSerial No. 301,313, filed July 28, 1952, now abandoned, entitledReciprocating Mounting Means for Mounting Thereon a Sanding or LikeTool, which is in turn a continuation-in-part of my application SerialNo. 97,663, filed June 7, 1949, entitled Sanding and Polishing Machine.

What is claimed is:

1. A manually manipulatable fluid pressure operated reciprocatoryvibratory mechanism comprising a base plate, on which may be mounted awork engaging tool; a motor having a cylinder and a free floating pistontherein said cylinder having only contact mounting on said. base plate;and a housing member extending over and independently of and forming nopart of said motor and in spaced relation thereto mounted on said baseplate, by a flexible means, an upper portion of said housing memberfunctioning as a grasping member as a handle.

2. The mechanism of claim 1 further comprising the 10 flexible means ofa form exhibiting three dimensional resiliency connecting said housingmember to said base plate.

3. The mechanism of claim 1 further comprising the flexible means of acorrugated accordion-like acting longitudinal walls directly disposed onsaid base plate.

4. The mechanism of claim 1 further comprising a pressure fluid conduitextending from a source of pressure fluid to said housing member; avalve in said conduit controllable from said handle governing theadmission of fluid pressure to said motor; and a conduit extending fromsaid valve member to said cylinder of said motor, a portion of whichconduit comprises a flexible member.

5. The mechanism of claim 1 further comprising a pressure fluid conduitextending from a source of pressure fluid to said housing member; avalve in said conduit controllable firom said handle governing the flowof fluid pressure, a portion of said conduit being of a flexiblecharacter and a portion extending through the base plate to saidcylinder.

6. The structure of claim 1 further comprising a separating memberseparating the upper portion of said housing from said motor, saidmember having vents therethrough permitting the escape of exhaust airfrom the motor to pass therethrough; and sound deadening fibrousmaterial positioned in said housing member above said separating member.

7. The mechanism of claim 4 further comprising whereby the free floatingpiston of said motor may continue to reciprocate even though the baseplate is held stationary.

References Cited in the file of this patent UNITED STATES PATENTS1,115,704 Manes Nov. 3, 1914 1,276,167 Brown Aug. 20, 1918 1,768,942Szewczyk July 1, 1930 1,953,534 Everett Apr. 2, 1934 1,954,489 PartlowApr. 10, 1934 2,221,448 Goodstein Nov. 12, 1940 2,245,545 Miller et a1.June 10, 1941 2,251,329 Ekstrom Aug. 5, 1941 2,272,008 Kehle Feb. 3,1942 2,367,668 Champayne Jan. 23, 1945 2,393,592 Crosby Jan. 29, 19462,643,731 Schmidt Jan. 30, 1953 2,821,962 Swanson Feb. 4, 1958

